BionX Electric Bike Conversion


by Jim Weaver, Service Manager, Fit Werx VT  

While not our normal product postings, this conversion was fun and I thought worth sharing.  We recently did an interesting conversion on a pair of mountain bikes.  Our clients had been in Switzerland, and had rented electrically assisted bicycles.  These were not strictly electric bikes, meaning that they were propelled by a electric motor.  Instead, the bikes were electrically assisted; electric motors augmented the rider’s pedal input.  They enjoyed these so much that they decided to convert their two mountain bikes to electrically-assisted bikes.

            The whole concept of an electric bike is interesting, at least for some riders.  In the case of the BionX conversion kit we used, the electric motor is housed in the rear wheel hub.  The rather large, lithium ion, 48 volt battery is mounted on the down-tube where a water bottle mount would normally be.  The motor will not do anything unless the rider is pedaling.  However, once going, the rider can select from four levels of assist: 35%, 75%, 150%, and 300%.  For example, at 150%, if I am pedaling at 100 watts, the motor will contribute another 150 watts, for a total of 250.  At 300%, that increases to a total of 400 watts!  That is a lot of power.   When coasting, the motor turns into a generator, charging the battery, much like a hybrid automobile.  When braking, the wheel also goes into regeneration mode.  Finally, if you wish, you can select total regeneration mode, whereby the motor no longer provides any assist, but rather turns into a generator to recharge the battery.  The range, under ideal conditions, and using only the 35% boost setting, is 65 miles.  Of course, the higher the power setting, the quicker the battery will drain.

            I must say, it was great fun test riding these bikes.  I passed Ian, out walking his dog, while I glided up a hill, seated, in the biggest gear the bike had.  He said I had a grin on my face from ear to ear.  While the system is heavy, the rear wheel alone weighing about 12 pounds, the increase in power far exceeds the additional weight.  A BionX powered bike is a real hoot and would make sense for just about anyone looking to make their commute, ride around town or the like easier!  Electrically assisted bikes are a very small, but growing, segment of the bike industry.  It will be interesting to watch the development of this technology; they certainly have a place in the world making a form of cycling more accessible to a wider range of people or just making you feel like you are superman (or woman) as you climb that next hill with triple your normal power. 


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